Quick connector

ABSTRACT

A quick connector includes a female portion with a staggered bore whereof one cross-section with large diameter can receive an outer flange of a male portion of the connector beyond a lock, the lock including a ring having an orifice for allowing through the flange and mounted in a housing provided in the female portion at the cross-section with large diameter of its bore to slide radially in the housing between a first inactive locking position wherein the passage orifice of the ring is eccentric relative to the axis of the bore and a second retracted position wherein the passage orifice is substantially coaxial with the bore. The lock further including a locking indicator mounted radially sliding in the ring between a first indicating position wherein the locking indicator does not obstruct the passage orifice and a second indicating position wherein the locking indicator obstructs the passage orifice.

CROSS REFERENCE TO RELATED APPLICATIONS

This is the 35 USC 371 National Stage of International ApplicationPCT/FR02/02247 filed on 28 Jun. 2002, which designated the United Statesof America.

FIELD OF THE INVENTION

The present invention relates to a quick connector comprising a malepart and a female part which are coupled together merely by insertingone in the other.

BACKGROUND OF THE INVENTION

In circuits that convey fluids under pressure and that make use of quickconnectors, it is desirable, and often required, to make use of meansthat lock a connection in positive manner. A badly-made connection isfirstly a source of leakage, and secondly runs the risk of decoupling,where the least severe consequence is a breakdown of the machineincluding said pressurized fluid circuits, and if the machine is a motorvehicle, a more severe consequence could be to lead to an accident (nopressure in the hydraulic brake circuit, fuel leaking into the enginecompartment possibly leading to a fire, . . . ).

Numerous devices exist for locking the male element in the femaleelement of a quick connector. Substantially all of them operate on thesame principle and implement identical general means consisting in akeying member which is interposed between a radial surface of theendpiece (a groove or a collar) and a radial surface of the femaleelement (likewise a groove or a collar). The keying member may beinserted manually or it may be held in its locking position by aresilient return member, the keying member being suitable, while theendpiece is being inserted, for being put into a retracted positionagainst the force of the return member (either by being displaced or bybeing deformed).

In a particularly simple embodiment of such a device as described indocument FR 2 705 430, the latch is constituted by a ring mounted toslide radially in a housing formed in the female part of the connectorbetween a rest and locking first position in which it is off-centerrelative to the axis of the bore of the female part, and a retractedsecond position in which it lies substantially on the axis of said bore.

A resilient member constituted by two tongues made integrally with thering is interposed between the ring and the female part, and urges thering towards its first position after the collar has passed through.

It is found that that mode of locking does not provide sufficientguarantee that the male part has been properly engaged in the femalepart. The male part can be engaged sufficiently for the collar to forcethe ring to move against the return tongues, but not far enough for thecollar to clear the ring, thereby preventing the ring from taking up itslocking position behind the collar under drive from the elastic tongues.This situation is not blatantly visible to the operator, who mightbelieve that the connection has been made properly.

Documents EP 0 505 930, EP 0 846 907, FR 2 705 432, and U.S. Pat. No.6,145,886 disclose connectors fitted with locking indicators thatindicate that the connector has been locked properly, the lockingindicator being disposed downstream from the locking member so as to bedriven by the collar after it has gone past the locking member. In theconnectors illustrated in those documents, the female part has specialopenings to enable co-operation between the locking indicator and thecollar of the male part while it is being inserted, thereby weakeningthe female part and making it more complicated to manufacture.

In document EP 0 992 729, the locking indicator is likewise disposed inan axially off-center position relative to the locking member, butupstream from the locking member at the end of the female part. Thelocking indicator is driven not by the collar of the male part, but byan accessory entrained by the male part on being inserted in the femalepart, thereby making that type of connector more complex.

OBJECTS AND SUMMARY OF THE INVENTION

The invention seeks to remedy those drawbacks, and more precisely itprovides a quick connector comprising a female part with a stepped borehaving a larger-diameter section suitable for receiving an externalcollar of a male part of the connector beyond a latch, the latch beingconstituted by a ring having a through orifice for passing the collarand of a diameter close to that of the collar, the ring being mounted ina housing formed in the female part at the larger-diameter section ofits bore to slide radially in the housing between a rest and lockingfirst position in which the orifice of the ring is off-center relativeto the axis of the bore, and a retracted, second position in which thethrough orifice is substantially coaxial with the bore. According to theinvention, the latch includes a locking indicator mounted to slideradially in the ring.

Thus, the locking indicator of the invention is included without anyneed to provide special openings in the female portion of the connector,and without any additional parts or accessories. The connector is thusunchanged overall, with only the ring being modified to receive thelocking indicator.

In an embodiment, the locking indicator is movable in the ring between afirst reference position in which the locking indicator does notobstruct the through orifice in the ring, and a second referenceposition in which the locking indicator obstructs said through orifice.

In order to verify the connection between the male part and the femalepart has been made correctly, the operator in charge of making theconnection is required to drive in the locking indicator of theinvention after the male part has been inserted in the female part.

If it is possible to move the locking indicator into the secondreference position, then it obstructs the through orifice in the ringfor passing the collar. This thus constitutes a sure sign that thecollar is no longer in the orifice, since otherwise the presence of thecollar would have prevented the locking indicator from moving.

In contrast, if it is not possible to move the locking indicator intothe second position, then the male part has not been engaged far enoughinto the female part to ensure that the collar has gone past the ring.

The locking indicator thus acts as an indicator of good connectionbetween the male part and the female part, thus serving to guaranteethat the connection is of good quality.

In a preferred embodiment, the locking indicator and the ring includemeans for preventing them from moving relative to each other when thelocking indicator is in one or the other of the reference positions.

On passing through the orifice in the ring, the collar pushes away thelocking indicator until it no longer obstructs the through orifice. Thelocking indicator is then in the first reference position, and it isprevented from moving relative to the ring by the means provided forthat purpose. When the collar has gone past the ring, the ring movesinto its rest position, and the locking indicator remains held in itsfirst reference position, until the operator drives it manually towardsthe second reference position where it is again prevented from movingrelative to the ring.

These means for preventing it from moving serve to guarantee that thelocking indicator is stationary relative to the ring and cannot movebetween the two reference positions unless deliberately driven by theoperator.

Preferably, and prior to making a first connection, the lockingindicator and the ring are secured to each other by means of a temporaryconnection in an intermediate position between the first and secondreference positions, the intermediate position being selected in such amanner that the locking indicator obstructs the through orifice in thering.

Thus, before any connection, the locking indicator is held in anintermediate position which can be recognized visually and/or tested byattempting to move the locking indicator slightly, thereby enabling theoperator to know immediately whether the female part has already beenused or not. Furthermore, the ring and the locking indicator can thus bemanufactured as a single part, thereby simplifying manufacture andassembly of the connector.

By way of example, the temporary connection is constituted by ligamentsjoining the ring to the locking indicator together, the ligaments beingbroken on first connection when the collar passes between the ring andthe locking indicator.

According to a characteristic of the invention, the intermediateposition is such that the distance between the locking indicator and theendpiece of the male part is less than a displacement stroke of the ringin the housing.

Thus, when the male part is engaged in the female part without thecollar going past the through orifice, the effect of the operatorpressing on the locking indicator will be to press the ring against theflexible tongues. The locking indicator will then come into abutmentagainst the endpiece of the male part prior to the ring coming intoabutment against the bottom of the housing. The temporary connectionbetween the ring and the locking indicator will not be broken and whenthe operator ceases to press on the locking indicator, it will move backup together with the ring. The operator thus has visual proof that theconnection has not been made properly.

According to an aspect of the invention, the locking indicator includesa drive portion projecting outside the female part when the lockingindicator is in the first position, and substantially retracted into thefemale part when the locking indicator is in the second position.

The drive portion has an opening for receiving a driving tool, theopening being accessible when the locking indicator is in the secondreference position.

When the drive portion is pushed into the female part, it is no longerpossible to take hold of it with the fingers in order to drive thelocking member. To be able to drive the locking member, it is necessaryto insert a tool in the opening through a rear setback formed in thefemale part and giving a tool access to the opening.

The locking indicator also has flanges extending the drive portiontowards the inside of the ring housing, the flanges in part facing theend walls of the housing, at least when the locking indicator is in thesecond reference position.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be better understood in the light of the followingdescription of an embodiment of the invention with reference to theaccompanying figures, in which:

FIG. 1 is a longitudinal section view on line I-I of FIG. 3 showing aquick connector of the invention, the male part being inserted in thefemale part, the ring being in the rest position while the lockingindicator is in the first reference position;

FIG. 2 is a section view of the quick connector on line II-II of FIG. 1passing through the housing for the ring and the locking indicator, themale part being removed, the ring being in the rest position while thelocking indicator is in an intermediate position between the first andsecond reference positions;

FIG. 3 is a view analogous to FIG. 2 during insertion of the male partinto the female part, the ring being in the retraced position while thelocking indicator is in the first reference position;

FIG. 4 is a view analogous to FIG. 2 at the end of insertion of the malepart into the female part, the ring being in the rest position while thelocking indicator is in the first reference position;

FIG. 5 is a view analogous to FIG. 2, after the locking indicator hasbeen moved into the second reference position, the ring being in therest position; and

FIG. 6 is a view analogous to FIG. 2, showing a situation in which onlythe endpiece of the male part has been engaged.

DETAILED DESCRIPTION OF THE INVENTION

For reasons of clarity, the male part, the ring, and the lockingindicator are not shown in section in FIGS. 2 to 6.

With reference to FIG. 1, a connector of the invention comprises afemale part 1 extending along a longitudinal axis and subdivided into aplurality of sections. A first section 2 of diameter d serves to receivethe cylindrical endpiece 25 of a male part 21. O-rings 26 are disposedin the female part 1 so as to bear against the endpiece 25 of the malepart 21 in order to seal the connection. A second section 3 of largerdiameter D is provided to receive an external collar 22 on the male part21. The section 3 is provided with a housing 4 defined by two plane endwalls 18, 18′ extending perpendicular to the axis of the female part 1and providing a passage for radial sliding of a ring 5 in the housing 4.According to the invention, the housing 4 also receives a lockingindicator 8 described in greater detail below.

As can be seen more clearly in FIG. 2, the ring 5 comprises inconventional manner resilient tongues 6 bearing against the bottom ofthe housing 4 and exerting a return force towards the rest position ofthe ring 5 as defined by steps 19 in the housing 4 co-operating withsteps 20 on the ring 5.

The ring 5 also has a conical surface 7 extending in a cone to acircular edge 27 of diameter slightly greater than the diameter D of thelarger section 3. The edge 27 defines a portion of a circular throughorifice 28 allowing the collar 22 to pass through the ring 5.

The through orifice 28 is represented herein solely by the edge 27, butit must be understood as being a virtual orifice passing through thering along an axis parallel to the axis of female part 1, bearingagainst the edge 27, and being cylindrical in shape with a diameterslightly greater than the diameter of the collar 22.

In the position shown in FIG. 2, the through orifice 28 is offsetrelative to the axis of the female part 1. The conical surface 7 allowsthe end 25 of the male part to pass freely into the section 2, butconstitutes an obstacle against insertion of the collar into the section3 downstream from the ring 5.

According to the invention, the female part 1 is fitted with a lockingindicator 8. The locking indicator 8 comprises a drive portion 9projecting from the ring 5. For this purpose, the ring 5 is open andpresents two branches 10 whose ends 11 face the sides of the driveportion 9.

Two flanges 13 extend from the drive portion 9 having their endsconnected to the ring 2 via breakable ligaments 14. Each flange 13possesses a bearing portion 17 facing towards the inside of the housing4, so that the bearing portion 17 is substantially tangential to avirtual cylinder of diameter D extending along the axis of the femalepart and extending the larger section 3.

The ring 5 and the locking indicator 8 are advantageously manufacturedtogether, e.g. by injection molding a plastics material, thusfacilitating manufacture and installation in the housing 4.

Once the ligaments 14 are broken, the locking indicator 8 can be movedradially between a stable first reference position in which the ends 11of the branches 10 of the ring 5 snap into lateral recesses 15 at thebase of the drive portion 9, and a stable second reference position inwhich the ends 11 snap into lateral recesses 16 at the top of the driveportion 9.

So long as the ligaments 14 have not been broken, the locking indicator8 is in an intermediate position between the two reference positions,the intermediate position being selected in such a manner that thelocking indicator 8 obstructs the through orifice 28. In FIG. 2, it canbe seen that the locking indicator 8 projects from the female part 1,the drive portion 9 being halfway into the female part 1, thus informingan operator immediately that the locking indicator 8 is in theintermediate position.

In FIG. 3, the male part 21 represented by the collar 22 and the tubularportion 23 is shown while it is being inserted. The cylindrical end 25(not shown in this figure) of the male part 21 has been slid between thering and the locking indicator so as to be inserted into the section 2of the female part, and it has been possible to slide the collar 22under the bearing portions 17 of the flanges 13 of the locking indicator8, but it has come into abutment against the conical surface 7 of thering 5.

By forcing the male part 21 into the female part 1, the ligaments 14holding the locking indicator 8 to the ring 5 give way, therebyseparating the ring 5 from the locking indicator 8. The ring 5 is thenfree to move radially under thrust from the collar 22 against theramp-forming conical surface 7 and against the return force exerted bythe flexible tongues 6, until the bearing portions 17 of the lockingindicator 8 come to bear against the periphery of the collar 22. Thering 5 moves until the edge 27 of the conical surface 7 passes under thecollar 22, which is the position shown in FIG. 3. In this position, thethrough orifice 28 is centered on the axis of the female part 1, and thelocking indicator 8 is held by the periphery of the collar 22 so that itdoes not obstruct the through orifice 28. The collar 22 can then passbetween the ring 5 and the locking indicator 8.

It should be observed that in this position the ends 11 of the branches11 of the ring 5 have snapped into the lateral recesses 15 of thelocking indicator, such that the locking indicator is in the firstreference position.

In order to facilitate passage of the collar between the ring 5 and thelocking indicator 8, it is possible to provide cam surfaces on theflanges of the locking indicator at the bearing portions 17.

In FIG. 6, there can be seen a situation in which the male part,represented by the endpiece 25, has been engaged partway into the femalepart, but without the collar 22 reaching the ring 5.

If the operator presses on the drive portion 9 of the locking indicator8, the ring/indicator assembly is pushed against the flexible tongues 6and it can be seen in the situation as illustrated in this figure thatthe locking indicator comes into abutment against the endpiece 25, whilethe ring 5 is not in abutment against the bottom of the housing 4, asrepresented in the figure by clearance J between the ring 5 and thebottom of the housing 4. It is therefore not possible for the ligaments14 to be broken, and when the operator ceases to apply thrust, thelocking indicator 8 rises together with the ring 5 in order to return toits initial position, i.e. the intermediate position.

To ensure that there is clearance J between the ring 5 and the bottom ofthe housing 4, it is necessary, as shown in FIG. 2, for the distance hbetween the locking indicator 8 and the endpiece 25 to be less than thestroke c in the housing 4.

The operator can thus see that the connection has not been made.

In FIG. 4, the collar 22 has gone past the ring 5 and the ring hasreturned to its initial position under the return force exerted by theflexible tongues 6. The through orifice 28 is again off-center, thelocking indicator 8 then being in the first reference position, with thedrive portion 9 clearly projecting from the female part 1.

In this position, the branches 10 of the ring are facing the plane endwalls 18 and 18′ of the housing 4, while the ring 5 possesses a wallportion 29 facing the collar 22. The ring 5 forms a latchinterconnecting the male part and the female part and opposingwithdrawal of the male part. In order to reinforce such opposition, thering 5 is fitted with a bib 24 which, when the ring 5 is in the restposition, extends so as to face the plane end wall 18′ of the housing 4(not visible in FIG. 4).

In order to confirm the connection, the operator presses on the driveportion 9 of the locking indicator 8 so as to bring it into the positionshown in FIG. 5, which is the second reference position, and in whichthe ends 11 of the branches 10 of the ring 5 are snapped in the siderecesses 16 of the locking indicator 8.

If this operation is possible, that is because the collar 22 has indeedbeen engaged in the female part beyond the ring 5, so the ring has beenable to return to its initial, rest position.

Otherwise, the collar 22 constitutes an obstacle for the bearingportions 7 on the flanges 13 of the locking indicator 8, so theindicator cannot be pushed in, and a fortiori it cannot be placed in thesecond reference position. The operator immediately detects that theconnection has been badly made.

Should it happen that the collar 22 goes past the ring 5 but without thering returning to its initial position, for example because of thepresence of an obstacle or because one of the flexible tongues 6breaking, then the operator can see prior to applying any drive that thelocking indicator 8 has remained in a position close to the intermediateposition instead of being moved towards the first reference position. Ifthe operator were not to see this, and were to attempt to push thelocking indicator 8 towards the second reference position, it would notbe possible to snap the indicator into that position. The operator isthus likewise made aware that the connection is bad.

In the second reference position, the locking indicator 8 hardlyprojects at all from the female part 1, unlike the three situationsdescribed with reference to FIGS. 2 to 4. It is thus possible at aglance on observing the position of the locking indicator to verifywhether a connection has been made properly and confirmed by theoperator.

The locking indicator thus acts as a visual indicator of properconnection.

The lateral recesses 15 and 16 and the ends 11 of the branches 10 of thering 5 are arranged in such a manner that the force needed to separatethe locking indicator 8 from the first reference position and the forceneeded to engage the locking indicator 8 in the second referenceposition are less than the force needed to bend the flexible tongues 6of the ring 5.

In addition, moving the locking indicator 8 into the second referenceposition serves to reinforce the resistance to withdrawal of the malepart from the female part. As can be seen in FIG. 5, the major fractionsof the flanges 13 and of the base of the drive portion 9 of the lockingindicator 8 are facing the collar 22 and thus project into the throughorifice 28 of the ring, while the ends of the flanges 13 and the top ofthe drive portion 9 of the locking indicator 8 are facing the end walls18, 18′ of the housing 4. The locking indicator thus constitutes anobstacle against withdrawal of the male part 21 from the female part 1.

The locking indicator 8 thus also acts as a latch, adding its effect tothat of the ring 5 so as to increase the force required to tear the malepart out from the female part.

In order to disconnect the male part from the female part, it isnecessary to replace the locking indicator in the first referenceposition. Since the drive portion 9 is pushed into the housing 4, it isnot possible to move the locking indicator 8 by hand. It is necessary toinsert the end of a tool into a slot 25 formed in the end of the driveportion 9 of the locking indicator 8 and to pull the locking indicator 8back into the first reference position. It is therefore not possible toreplace the locking indicator 8 unintentionally in the first referenceposition after it has been placed in the second reference position.

It should be observed that the slot 25 is accessible only from behindthe ring 5, as represented in FIG. 1 by arrow 50. When the lockingindicator 8 is in the second reference indicator, the slot 25 is levelwith the arrow 50 and access thereto from the other side is prevented bythe presence of an extension 51 on the female part that serves toincrease the area against which the locking indicator 8 bears againstthe female part 1.

Thereafter, it is necessary to press against the branches 10 of the ring5 in order to retract the ring to a position similar to that shown inFIG. 2. The collar 22 can then pass between the ring 5 and the lockingindicator 8.

The invention is not limited to the particular embodiment describedabove, but on the contrary extends to cover any variant which comeswithin the ambit of the invention as defined by the claims.

In particular, although it is stated that the locking indicator and thering are made together, the invention also applies to a lockingindicator that is independent from the ring. Under such circumstances,the locking indicator can likewise be held in the intermediate positionby snap-fastening means, or by a small spot of adhesive on the ends ofthe branches of the locking indicator. The intermediate position couldequally well not exist, with the locking indicator being initiallyplaced in the first reference position on assembly, or prior toinserting the male part.

Although it is stated that the locking indicator is snap-fastened to thering in the first and second reference positions, the invention appliesmore generally to a locking indicator and a ring having mutual lockingmeans. For example, it is possible to envisage a mere braking effect inthe first reference position since the indicator is not destined toremain therein for a long time, while positive locking could be providedfor the second reference position, e.g. by interposing a keying membersuch as a pin, or the like.

1. A quick connector comprising: a latch, a female part (1) with astepped bore having a first section (2) suitable for sealingly receivingan endpiece (25) of a male part (21), and a second section (3) of largerdiameter suitable for receiving an external collar (22) of the male part(21) beyond the latch, the latch being constituted by a ring (5) havinga through orifice (28) for passing the collar (22) and of diameter closeto the diameter of the collar (22), the ring (5) being mounted in ahousing (4) formed in the female part (1) in the larger-diameter section(3) of its bore to slide radially in the housing (4), in a directionperpendicular to the axis of the bore, between a rest and locking firstposition in which the through orifice (28) in the ring (5) is off-centerfrom an axis of the bore, and a retracted, second position, in which thethrough orifice (28) is substantially coaxial with the bore, wherein thelatch includes a locking indicator (8) mounted to slide radially in thering (5) and relative thereto, in a direction perpendicular to the axisof the bore, and being movable under voluntary operation between a firstreference position within the ring indicating that the collar (22) hasgone past the ring (5), and a second reference position within the ringindicating that the male part (21) has been locked properly, the ringand the locking indicator further comprising mutual locking means (11,15, 16) for selectively securing the locking indicator (8) to the ring(5) in each of the reference positions so that the locking indicator (8)and the ring (5) are prevented from moving relative to each other whenthe locking indicator is in one of the reference positions.
 2. A quickconnector according to claim 1, wherein, in the first referenceposition, the locking indicator (8) does not obstruct the throughorifice (28) of the ring (5), and in the second reference position, thelocking indicator (8) obstructs said through orifice (28) so as to forman obstacle to the collar (22) passing therethrough, therebycontributing to locking of the male part into the female part.
 3. Aquick connector according to claim 1, wherein, prior to making a firstconnection, the locking indicator (8) and the ring (5) are secured toeach other by means of a temporary connection in an intermediateposition between the first and second reference positions, theintermediate position being selected in such a manner that the lockingindicator (8) obstructs the through orifice in the ring (5).
 4. A quickconnector according to claim 3, wherein the temporary connection isconstituted by ligaments (14) joining the ring (5) to the lockingindicator (8), the ligaments (14) being broken on first connection whenthe collar (22) passes between the ring (5) and the locking indicator(8).
 5. A quick connector according to claim 3, wherein, when thelocking indicator (8) is held to the ring (5) in the intermediateposition, the distance (h) between the locking indicator and theendpiece (25) of the male part (21) is less than a displacement stroke(c) of the ring (5) in the housing (4).
 6. A quick connector accordingto claim 1, wherein the locking indicator (8) includes a drive portion(9) projecting outside the ring (5) when the locking indicator (8) is inthe first position, and substantially retracted into the female part (1)when the locking indicator (8) is in the second position.
 7. A connectoraccording to claim 6, wherein the drive portion has an opening (25) forreceiving a driving tool, the opening (25) being accessible when thelocking indicator (8) is in the second reference position.
 8. A quickconnector according to claim 1, wherein the locking indicator includesflanges (13) extending from the drive portion (9) towards the inside ofthe housing (4) for the ring, the flanges facing in part end walls (18,18′) of the housing (4), at least when the locking indicator (8) is inthe second reference position.
 9. A quick connector according to claim1, wherein the mutual locking means comprises: branches (10) having ends(11) that extend from the ring (5); first recesses (15) on the lockingindicator (8) in which the ends of the branches snap when the lockingindicator is brought to the first reference position; second recesses(16) on the locking indicator (8) in which the ends of the branches snapwhen the locking indicator is in the second reference position, whereinsnapping of the ends in the first or second recesses causes the lockingindicator and the ring to be mutually locked.
 10. A quick connector,comprising: a male part (21) having an endpiece (25) and an externalcollar (22); a latch; a female part (1) with a stepped bore having afirst section (2) to sealingly receive the endpiece (25), and a secondsection (3) of larger diameter to receive the external collar (22) ofthe male part (21) beyond the latch, the latch constituted by a ring (5)having a through orifice (28) for passing the collar (22); a housing(4), within the larger-diameter second section (3) of the female part(1), mounting the ring (5); the ring (5) being mounted in the housing(4) to slide radially in the housing (4), in a direction perpendicularto an axis of the bore, between i) a rest and locking first position inwhich the through orifice (28) in the ring (5) is off-center from theaxis of the bore, and ii) a retracted, second position, in which thethrough orifice (28) is substantially coaxial with the bore; a lockingindicator (8) included in the latch and mounted to slide radially in thering (5), in a direction perpendicular to the axis of the bore, andbeing movable relative to the ring, under manual operation, between i) afirst reference position indicating that the collar (22) has gone pastthe ring (5), and ii) a second reference position indicating that themale part (21) has been locked properly, the ring and the lockingindicator having mutual locking means (11,15,16) for securing thelocking indicator to the ring when the locking indicator is in one ofthe reference positions so that the locking indicator (8) and the ring(5) are prevented from moving relative to each other when the lockingindicator is in one of the reference positions.